Random Variables - Code error?

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Random Variables - Code error?

Daniel Schonfeld

posted May 12, 2019

In Lecture 11, about Random Variables I'm confused with why at the end, the code for normal fitting is:

sample_distribution = ((1/np.sqrt(sample_std_dev * sample_std_dev * 2 * np.pi)) *  
                       np.exp(-(x - sample_mean)*(x - sample_mean) / (2 * sample_std_dev * sample_std_dev)))

and in the exercises it's this code:

sample_distribution = ((1/(sample_std_dev * 2 * np.pi)) *  
                       np.exp(-(x - sample_mean)*(x - sample_mean) / (2 * sample_std_dev * sample_std_dev)))

Shouldn't both be sample_std_dev*np.sqrt(2*np.pi) ?

It's probably my meager math and I'm just missing something very obvious... if that's the case can someone explain what we're trying to do here?

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In addition, the material offers no opinion with respect to the suitability of any security or specific investment. No information contained herein should be regarded as a suggestion to engage in or refrain from any investment-related course of action as none of Quantopian nor any of its affiliates is undertaking to provide investment advice, act as an adviser to any plan or entity subject to the Employee Retirement Income Security Act of 1974, as amended, individual retirement account or individual retirement annuity, or give advice in a fiduciary capacity with respect to the materials presented herein. If you are an individual retirement or other investor, contact your financial advisor or other fiduciary unrelated to Quantopian about whether any given investment idea, strategy, product or service described herein may be appropriate for your circumstances. All investments involve risk, including loss of principal. Quantopian makes no guarantees as to the accuracy or completeness of the views expressed in the website. The views are subject to change, and may have become unreliable for various reasons, including changes in market conditions or economic circumstances.